/Engine/Source/Runtime/Engine/Classes/PhysicsEngine/ConstraintDrives.h
struct FConstraintDrive
uint8:  1
bEnablePositionDrive
Enables/Disables position drive (orientation if using angular drive)
uint8:  1
bEnableVelocityDrive
Enables/Disables velocity drive (angular velocity if using angular drive)
float
Damping
The damping strength of the drive. Force proportional to the velocity error.
float
MaxForce
The force limit of the drive.
float
Stiffness
The spring strength of the drive. Force proportional to the position error.